Forehearth construction



Janv. 29,

1952 M. M. OANNON, JR 2,583,629

FoREHEARTH CONSTRUCTION Filed Jan. 29, 1947 f s l 5a. 56 56 Z0 23 ze 4619 53d. 61 l 60a Z Fia.' 2,

INVENTOR MADISON M. CANNON JR.

ATTOR NEYS Patented Jan. 29, 1952 FOBEHEABTH ooNs'rnUo'rioN Madison M. Cannon, Jr.,

assignor to Emhart Ma a corporation of Delawa West Hartford, Conn., nufacturing Company, re

Application January 29, 1947, Serial No. 725,097

2 Claims.

This invent-ionl relates to improvements in forehearths for receiving molten glass from a melting tank or like source of supply and for conducting such glass to a delivery chamber, such as a feed bowl or basin located at the outer end of the forehearth, and from which glass is to be fed, gathered or otherwise removed.

The invention more particularly relates to improvements in forehearths of that type which have a rear or upstream so-called cooling section and a forward or downstream so-called heating or homogenizing section, the outer end portion of which constitutes the delivery chamber of the forehearth.

Heretofore, in the operation of forehearths of this type, cooling has been effected and the temperature regulated in the cooling section in a variety of ways, all of which involve heat conduction, or radiation, or both. Examples of practices heretofore used with success are described in Patent No. 2,139,911 granted December 13, 1938, to Peiler et al. and Patent No. 2,144,973 granted January 24, 1939, to Honiss. For a more complete appreciation of the present invention, reference should be made to those patents.

In the operation of forehearths of the type to which reference has been made, the temperature of the glass in the cooling section is` :regulated primarily, as the designation of the section implies, by cooling, with a view to obtaining for all the glass leaving the cooling section an average temperature corresponding to the temperature desired at the outlet or point of removal of glass from the delivery chamber. During the travel of such glass through the outer or homogenizing section, an attempt iscmade to eliminate temperature differences between dfferent portions of the glass while preventing or compensating for further further loss of heat from the glass. This may be done by applying a regulated amount of heat to the 4glass in the homogenizing section, the object being to allow all the glass to even out as to temperature, or uniformly attain the temperature desired and to be homogeneous while in the delivery chamber or at least when in that portion of the delivery chamber that contains the feed outlet or place at which glass is to be removed.

`Since the glass moving from a. melting tank or like source of supply through the forehearth to the delivery chamber tends to become cooler and to flow more slowly next to the Walls of the forehearth channel, it is usual to provide some means in an attempt to bring the temperature and rate of flow of the side or edge portions of the, stream and of the remainder of the stream into substantial correspondence. Such means may comprise means for permitting cooling of the middle portion of the glass, as by radiation to and conduction through the top wall of the cooling section of the forehearth while heat loss from the glass of the side or edge portions of the stream is substantially reduced or opposed, as by the application of heat thereto.

The temperature of the glass` passing from the refining end of a melting tank or like source of supply to a forehearth usually is higher than that desired at the outlet or point of removal of glass from the delivery chamber. The reduction of temperature to be eifected may be relatively slight, as when the glass to be fed or otherwise removed is to be at a relatively high temperature, suitable for the production of small charges which are tobe manufactured into small articles of glassware. When the charges are relatively large, as for the manufacture of larger articles of glassware, the reduction of temperature is greater and may be as much as 300 to 400 degrees greater than the reduction required for charges for small Ware.

The types of glass, i. e., high and low temperature glasses are additional factors which further increase the temperature operating range necessary in a foreheath which will satisfy all possible service conditions. Also, the temperature of the glass entering the foreheath may be different in different installations and even at different times in the same installation. Still further, the factors governing the condition of the glass will be different when the output of glass from the delivery chamber per unit of time is varied, even though there has been no change of temperature in the glass entering the forehearth and the same temperature is desired at the feed outlet or point of delivery of glass from the delivery chamber.

I'he aforementioned patents to Peiier et al, and to Honiss disclose forehearth constructions and methods of operation which have given satisfactory operation over a wide range of service` conditions. In the former patent, cooling is effected by radiation of heat from the molten glass to the roof of the cooling section and by conduction and radiation through and from the roof. The transfer of heat through the roof by conduction may slow up the cooling to a co'- siderable degree. However, the patent points out that, if necessary, a higher cooling rate can be established by enlarging the size of the upstream apart from. anyl transfer through.

Ywhich travels at much slower speed In some instances, particularli `illlreure temperature melts are being run or the chemi cal composition of the glass mayfbe suchthat cor.-

Yrosive gases are discharged which "attack the refractory material commonly used in forehearth construction, the forced circulation of coolant max accelerate deterioratinwof nthe ,refractory materials lwhiclnform the vents and Vassociated ducts and.passae es.. The present. intention provides los, .the .neoeer sary. terrlperature control of the, coolingv sections without.utiliaingjonced circulations and, lat the sameltirne, .obtansarnaximurnpseof heat transreeby .radiation from .the Cooling seoionf...

`;. For a more .complete.understanding of ...ille present inyention.. the distinction. between heelt transfer rad.lationYV as contrasted,,with :trarls- :c

fer byaconduction-lshould be. borne. in. mind.A In roe.. iattentha transfer is. by direct ,transfer to .a.contactingmrnediumwhile Vin .tbeformer .the

transfer is maoedirectlr. ;to ,e roate rial .Speoesl from and at whiohthe. heat .source example, ,when..a highl heated loodylloh oath@ son looksat a colder bodnsueh. loathe-earth, beat is, transmitted. by.A radlatiomto the letter This.. radiant.,transieoofheat. is .made .entirely orthroush anlntermefliateor conveying medium, Suohesein Whohtouchinrstthelone another .thegotnen Heat transferredbyradiatlon travels at thei. speed .of light. Where ,heat transf,errecl by means of a conveying medium, sucha5 all?, moves, even under ,force 1 draft with: theauthan radiant cianttransfer to.a oonsiderable degree 1n oo..`

'.oination. with .natural circulation of.. a Cooling v.n iedium. .More particularly. provision i.sj made for the, surface of` the cooling. chamber .lrool which looks atithelsurfaoeof .the molten glass` to ,be adjnstably positlonableso. as. in turn,4 to look Yat tor .expose `.the .ambient or .colder .materials and `.objects outside o.fthe. f.or.ehearth.n yarlaole quali.'-

tity. or 'area t the radiant energy. .o f.- the. roof Vsurface. In accordance with this ,nvention the .roof surface is so.located as to look. at all or substantially all the moltenglasssurfaoe andpit ispossible. to dissipate amaxirnum amount of heat energnlquicklyby radiant transfer..

1 The. present invention has thefurther ativan A tage ofnroriding .for control ofcoolne atraenlahlerates Which, may.. .be substantiallynniforrn ithroughout the cooling section orA regulably varied as desired.

A 'still further advantageis. the provision-of maximum natural vdraft cooling which maybe Veffected more uniformly than heretofore,` and AVaried more uniformly. throughout. the length-'Gf the cooling section as operating conditions mai7 require- Y Y Still another v:is the V `sinfultaneo/ris regulation of cooling both by natural draft and byV radiant heat loss which may be effected by a single adjustment of the entire roof structure. VOther advantages will hereafter be pointed out .or will become apparent from the following description of an embodiment of the invention, as shownin the accompanying drawings, in which: l. Figure lis a longitudinal vertical section along line l--l of Fig. 2, illustrating a forehearth provided with glass temperature controlling and conditioning. means embodying the invention;

' V`.igjzisa cross-sectional view taken along the .lir 1.e.,2,2 of Fie.. .lrangd y Eig. 3 is an enlarged cross-sectional plan view 'of fa portion'of .the forehearth taken along line Referring "oiv vmore particularly to Fig. l,

Va forehearth is shown as comprising a rear or so-called cooling section I0 and an outer or .forward tlorlll- The outerlemlportion eithe Section 1l constitutes a deliyery chamber, designatedrl?.

VThe side walls and'bottoms ofthe foreharth ysectif'ms, um and 'l l, are lrefinedorsaitaaieierra; tory blocks or niemberswsuitably :connected Ato constitutev a, refractory flow channel i3. The outer endl'portion of'this dflow ,chann'ehindicated Vd bowl at lia, is shown as beingsafrefractory VYwhich is provided `at its Ybottom with; va feed outlaw. Thal-@faon"enameleresulteren: Suleted et ellpleoes deeleolesloy .the insulating erick. i5 Whichmay be onned and held in place against vthe refractory channel. a Vsuitalyleme l Fig.Y 1, the feed bowl lotxlaclis insulation, Ait will be understood thatin, actual practice, insulation .of au. Suitable kinoimar eee enel held in Place lo enyslllteble Knowher- .Also, in actual practice, v'suitable Asupportng'stru torelnotehownlwill. rhearth and the forehearthnwill be so located with .respect to. ameltioe tanker like eoiiroe of. Surely talliclcasing, such as indicated atvl.V

but i v ied horror/leed fol: thefore'- thatv glass yu lillwbe supplied continuously in a Stream. eelroieateo at ll lm .le- 1, .flomflille source of supply to the forehearth. The flow Channel thea. Wil.1. be.. eorltiououslrlle.l 'luth molter,l glass toeoredetermloeolerel. sement to meinteinforer elle feed outlet e.. body. of. elee ofsufflcient depth for the.feeding,operationst Only a portion.. ofV awallfthe. meltlnelenk .is Shown. theseme beirieirldioeted ,et L3. .Fiell as the present .nveotioaeloeeleot require. any lnovel. or.'Sneeielwer.of @oneetoethefforeheartll Wlthvth eooreeofllpely growers flowy channel n of accomplishingthis result are well known in the art.

ture, como 'siege Section .IS reel' or eoelioeeon lill .erection 2@ .top .el .the vheating.,01' llomoeenle. vanda section 2 l atthetopvof theL .ber l2, Preferably till Cover.. etroetllreefile forehearth is `soconstruote'd eas toprovd'e ubreetiellmflell .too Welle.. lor-.fthe 'Severe-l .Se 11S `of the vforeheaith.A The Ar fractoryhinner Walls ef. @tweeen eine' een A Y l f Vnre Inay'have insulating `briclgs.V superimposed thereon, as indicatedat23,Fg,l A. .Sutaloleyertloal opening may xloe formed through. the seotionl. of.tl1,e. .ooi/er, structure .above the .delivery ohaolber. to. eeeommodaie Sulteble meoheoemfol eontrollna theleeolina of glass throuehlleoullet, l meenemen belrereoreeellferl. ley ...the relttieel fefrae 'y plunger i4 and the vertical'refractory'tubev'.

so-called heatingY or homogenizingsec Y Since feeding mechanism, including these parts, forms no part of the present invention and is well known in the art, no further illustration or description thereof is required.

The heating or homogenizing section of the forehearth may be separated, above the level of the glass in the forehearth channel, from the rear or cooling section IU by a transverse refractory separator block 26. The space above the glass in the rear or cooling chamber IB likewise may be separated from the space above the glass in the associate melting tank or source of supply by a rear transverse refractory block, such as indicated at 21. This block may be spaced slightly from the adjacent wall I8 of the associate melting tank to provide a space, such as indicated at 28, for the sting-out of heated gases, the outlet at the top of this space being controlled by a suitable movable refractory cover block 29.

The sections I9 and I I and the delivery chamber I2 at the outer end of the latter may be provided with suitable heating means, preferably such as are included in the embodiment of the invention disclosed and claimed in the patent "of Karl E. Peiler and William T, Barker, Jr., No.

2,139,911, issued December 13, 1938, which is owned by the -owner of the present application. As shown, such heating means include closely spaced firing or combustion tunnels located in the side walls of the cooling chamber I, similar firing or combustion tunnels 3| in the side walls of the heating chamber II as far outwardly of the latter as the delivery chamber I2 and spaced ring or combustion tunnels 32 of a somewhat different form in the walls of the delivery chamber I2. All these firing or combustion tunnels are shown in Fig. 1 4as being located a predetermined distance above the level of the glass in the forehearth.

It will be noted from the showing of the firing or combustion tunnels 30 in Fig. 2 that each is substantially enlarged at its inner end portion, has its inner end downwardly and outwardly beveled, as at 30a, and has its bottom wall cut away for a substantial distance outwardly of this beveled portion, as indicated at 30h, Fig. 2, the effective bottom of the outer end portion of the firing or combustion tunnel being the exposed surface of the underlying or supporting refractory block 33.

Each firing or combustion tunnel 30 has a reduced inlet, indicated at 34 in Fig. 2, at the inner end of a counterbore in which is disposed the tip 35 of a nozzle 36.

As described so far, the structure is substantially as shown in the aforementioned patent to Karl E. Peiler :and William T. Barker, Jr., No. 2,139,911, which fully discloses and contains claims for patentably novel features thereof. Such structure has been described herein because it is particularly well adapted for cooperation with structure, hereinafter to be described, to produce a complete forehearth by which the objects of the present invention may be attained.

As shown, the section I9 of the cover structure for the cooling section I0 of the forehearth com,- prises refractory blocks arranged to constitute a flat crown 45 for the space above the glass in such cooling section. Spaced vertical vents or exhaust ports 46 are provided in this crown 45, preferably in the longitudinal median portion thereof.

Insulating bricks 41 surmount the vents 46, the bricks being spaced from the top of the arch 45 by means of the spacer blocks 48 so as to closure 45 is secured in its permit ow of flue gases through the vents to the atmosphere. The unsupported ends of the bricks 4'!` sufliciently overlie the vents 4B so that the bricks 4'! reflect substantially all of the radiant energy from the molten glass back through the vents into the interior of the glass chamber while at the same time negligibly restricting natural circulation of air from the vente 4B to the outside atrnosphere. i

In accordance with the invention, means are provided for adjustably supporting and positioning the arch assembly 45 with respect to the forehearth. Asshown in Figs. 1 and 2, the assembly of insulating brick constituting the arch or assembled position between a pair of laterally extending members 49 of U-shaped cross section having outwardly extending -ears 49a to the outer ends of which are pivotally pinned upwardly extending vertical arms 59. In order for the lateral members 49 to exert gripping pressure on the arch 45, the upper ends of the forwardly and the rearwardly disposed pairs of arms 50 are pivotally secured respectively to the ends of connecting members 5I land the lower ends of each pair of varms drawn inwardly by a tie rod 52 to thereby clamp the arch 45 between the members 49.

As illustrated in Figs. 1 and 2, wire cables 53 support the arch assembly at its four corners. The cables pass over pulleys 54 at the ends of shafts 55 horizontally disposed at either side of the forehearth. These shafts are rotatably journaled in suitable mountings provided in fixed yerticalsuports 56. The cables 53 are secured to winch drums 51, the forward pair of cables being secured to drums disposed at opposite ends of a shaft 58a mounted beneath the forehearth and the rearward pair of cables being similarly secured to drums carried by a second shaft 58h. The shafts 53a and 58h may be rotated to raise or lower' the arch 45, provision being made to raise or lower one end of the arch a greater or lesser amount than the other. To this end there are provided a pair of worm-'gear assemblies 59a and 59h manually operable by cranks 60a and 65D respectively, and connectable for simultaneous movement through a clutch 6I. Engagement of the clutch 6I permits both ends of the arch 45 to be simultaneously raised or lowered by rotation of either crank 50a or 60h whereas when the clutch 6I is disconnected the forward end of the arch can be raised or lowered independently by crank 60a and the rear end of the arch, likewise, can be independently raised or lowered by the crank BDb.

As best seen in Fig. 3, brackets 62 secured to the gripping members 4S are slidably engaged by the vertical supports 56 which thus act as guides to prevent lateral and fore-and-aft swinging movement of the arch 45 relative to the forehearth.

In the operation of a forehearth of the type illustrated and described, the arch or cover 45 for the cooling section of the forehearth may be adjusted so as to regulate the cooling conditions therein and regulate temperature under any contingency, both abnormal as well as normal, that is likely to be encountered in practice. For example, if the reduction of temperature of the glass passing through the cooling section of the forehearth is to be relatively slight, the cover or arch 45 can be located in its closed or very nearly closed position relative to the forehea'rth. In this position the amount of cooling air from the outside atmosphere entering the forehearth through the space between the arch and the foreir'rg'lthrough'the continuous, unirite Y 7 maan im be zere fer Ivery neasriy 'Hema gases pas-sing .but the irs wm be negiiiglibie and :cooling by air cireuiauon win 1be sught.

Furthermore, the exposure fof -the Aunder Lsurface f the arch tO the"ll'it'Sid'e1'atnlbielitsuiroilrdllg's'falfso willibethrzrb OiSxall. AThi-1S.,heal; losses byzradiuon from thefunderrfsufaceofthe arch '45 to the -outside will vbe correspondingly low. Of course, for any one position-oi the arch relative to the ihea'cii'ng chamber, 'small changes in y'teinperati'ire inayfbe effected b'y increasing 'or decreasing kthe application bf heat "'lin the burners. If, hwevelfjadju'stmehtf thebI'IIiQ'JIS is inufcifnt A't0 abcmilsh lthe "desired v"co'lirg, the entire :arch finay be lraisd and thefnecessay temperature adjustment "quickly obtained. It will be perceived that `ra1smg- -thejareh not romy wiu increase thecifcuiation df -jc'o "ing tiri-enter- V 'iipted space between Ythe archand "the cnarnbe Ynd parsfsi'ng out through f the 'Vents 46, butin laddition radiant energy from vthe 'molten glass absorbed by the face of thearch to themuc'h colder'fambientoiitside of the forehearth. -ItI-will be 'seenh'tliat'the 'arch is arranged to look at substantially `the entire surface of 'the `nilteii glass 'within the cooling Vsection of the fr'ehe'arth 'and consequently is Vadapted to "dissipate a `maximurn of heat 'energy by radiation 'of vthe foiltsl'de.

In addition to the iapidcontrol 'provide'd, the present invention hasthe further "advantage df roviding"-for disproportionate heatingror cooling inthe section of 'the foreheartli' controlled L by' the adjustableradant arch. Different cooling "rates f are readily established rmerely 'by 'raising A4or low ering the -ends of the'archtodiferentpositons relative `to"ea'ch` other. Thus whenthe 'rear "end of 'the farchfis-dispcsed iniahighenposition than the forward `ierid, ja l'gijea'ter degree of v*cooling Vis obtained io'rthe glass'as it'r'stfentersrthe ifore hearth 'anda predetermined lesser cooling rate is established for the 'glassinithefforward'end-of the coolingsectin prior to its 'passage into 'the li'omogenizing "Section fof lthe forheath.

It'will be "seen thatthenrSent 'invention "pro-n vides ar'apid 'temperature controlV utilizing i'radiant enerytan's'fel,

Theiin" 'entionffurther 'providesforfternperature 'control 'by rair "circulation or Ina-tural fcirc'ulatin containing v`molten glass having fa 'radi'an-t Yfsurface,

and a top structure movable-into and out fof sub- 'stantlal'ly Acontinuous Contact with yspaced Walls osai'd cooling section, said topfstructure'including :a radiant surface '-Which, between `'said 1spaced walls, "looks at and 'uncbstructe'dly covers fallof said radiant glass surf ace f and, *in `a -raised riposition Vnnb@ looks out "of said V"forenearth, v'and whereinthe 'top structure includes fan upwardly extending `passageway in yc'oitr'nnunication with the atmosphere'insidefandfoutsiiie the 'foreheartn "2k, A forehearth including `a cooling l-'se'ction containing lmolten glass having a radiant "surface, and atop structure movable into andout of substantially continuous contact with spaced walls of said cooling section, said top 'structure including a radiant surface which, between "said 'spaced walls,` looks at'and unobstructedly covers all f :said radiant glass surface and, ina raised Y position only,V looks "out of 'sai`d. orhearthy land wherein thet'op structure includes an upwardly extending l)passageway in communication with "the atmosphere .inside and outside the forehe'arth, and an insulating brick 'sur'xnounting said pas'- sageway and adapted t'o reiiect 'radiant energy from the molteii-gl'ass surface ba'ck through the 'passageway into the interior ofthe forehearth.

. MADISON MLCANNON, JR.

REFERENCES CITED 'The following references are 'of record "inthe file of this `patent: Y

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